25年长期定位不同施肥措施对关中塿土水力学性质的影响

土壤水力学性质和功能的变化是评价长期施肥是否维持土壤可持续健康发展的重要方面。该研究通过采取"国家黄土肥力与肥料效益监测基地"的表层原状土壤,分析测定了撂荒(LH)、休闲(XX)、不施肥(CK)、单施氮肥(N)、氮磷钾肥(NPK)和有机肥与氮磷钾肥配施(MNPK)6个处理的土壤水分特征曲线、饱和导水率和紧实度等指标,评价了长期定位施肥对土壤基本物理性质和水力学性质的影响。结果表明:1)与CK、N和NPK处理相比,MNPK处理显著提高了土壤有机碳、饱和导水率和孔隙度,而降低了土壤容重和紧实度(P0.05)。2)不同施肥处理之间的土壤水分特征曲线表现出一定的差异,其土壤持水能力强弱为:XXN≈NPKCKMNPKLH;MNPK处理较CK、N和NPK处理持水能力分别提高2.57%、3.33%和7.34%;V-G模型拟合结果表明残余含水量(θ_r)、饱和含水量(θ_s)和进气值倒数(a)都存在一定程度的差异,θ_r在MNPK处理最大,XX最小;θ_s在N处理最大,MNPK次之,CK最小。进气值(1/a)在XX处理最大,LH最小。3)当量孔隙的分布主要在9μm大孔隙范围内,其次是0.2μm小孔隙范围,0.2～9μm之间的中孔隙分布较少。综上,MNPK有助于改善土壤结构,提高土壤持水性,降低土壤容重和紧实度,有助于作物生长和高产,是关中地区较为适宜的施肥措施。     

Note: Evaluating insecticides for the control of overwintered adults ofEurygaster integriceps under field conditions in Turkey

The Sunn pestEurygaster integriceps Puton is the most harmful pest of cereals in Turkey and the surrounding countries. Chemical control has been employed against the nymph stages of the pest. The efficacy of six products [acetamiprid (SL, soluble concentrate), chlorpyrifosethyl (EC, emulsifiable concentrate), lambda-cyhalothrin (CS, capsule suspension), monocrotophos (SC, suspension concentrate), thiacloprid (SC) and zeta-cypermethrin (EC)] was tested on overwintered adults ofE. integriceps, with applications to wheat at the shooting stage. In a study conducted at Siverek, Şanlıurfa in the southeastern Anatolia Region, the most effective insecticide was found to be lambda-cyhalothrin. It gave very promising results in controlling the pest and reduced subsequent egg laying and the appearance of nymphs in the trial area. The results showed that chemical control of overwintered adults of the Sunn pest in early spring is possible with lambda-cyhalothrin. http://www.phytoparasitica.org posting Sept. 18, 2006.     

Numerical Analysis to Solve the Hydraulics of Trickle Irrigation Units

A model to solve the hydraulics of trickleirrigation units is developed in thisstudy. This model is based on utilizingNewton Raphson technique. The modelconverts laterals into equivalent outletsthrough utilizing a simple power relationbetween inlet lateral discharge andhydraulic head. This relation is obtainedthrough least squares analysis betweeninlet lateral discharge and hydraulic head. This study showed that this relation withonly two coefficients is sufficient todescribe the relation between inlet lateraldischarge and hydraulic head. Based onthis relation, the model converts manifoldlines into equivalent laterals and solvestheir hydraulics by Newton Raphsontechnique. After that solution, the modelevaluates trickle irrigation units byestimating statistical uniformity andChristiansen uniformity coefficients andchecks the solution obtained throughforward step method for each lateral. Several numerical examples for utilizingthe model are presented in this paper.Palestine Authority     

Effects of hypotaurine, cysteamine and aminoacids solution on post-thaw microscopic and oxidative stress parameters of Angora goat semen

This study was conducted to determine the effects of cysteamine, hypotaurine and aminoacids solution (BME) on standard semen parameters, lipid peroxidation and antioxidant activities of Angora goat semen after the freeze–thawing process. Ejaculates collected from four Angora goats were evaluated and pooled at 37 °C. Semen samples, which were diluted with a Tris-based extender containing the antioxidants hypotaurine (5 mM) and cysteamine (5 mM), and an aminoacid solution (13%), and an extender containing no antioxidants (control), were cooled to 5 °C and frozen in 0.25-ml French straws in liquid nitrogen. Frozen straws were thawed individually at 37 °C for 20 s in a water bath for evaluation.Supplementation with cysteamine, hypotaurine and BME caused significant (P < 0.05) increases in sperm motility, and significant (P < 0.05) decreases in total abnormality rates in comparison to the control group. While all in vitro treatments did not affect the acrosomal abnormality rates, hypotaurine and BME but not cysteamine significantly (P < 0.05) increased the HOST results as compared to the control group. Supplementation with antioxidants and BME did not significantly affect MDA levels and CAT activity in comparison to the control group (P > 0.05). The antioxidants hypotaurine and cysteamine decreased SOD activity when compared to the BME group and controls (P < 0.001).